String(v::Memory{UInt8}) doesn't make a copy

[nhz2]

The docstring of String says:

To avoid truncation
of Vector{UInt8} data, use String(copy(v)); for other AbstractVector types,
String(v) already makes a copy.

Since Memory is an AbstractVector, String should make a copy. However, it doesn't look like this is happening in:

julia/base/strings/string.jl

Lines 67 to 71 in 9d8e0e7

	function String(v::Memory{UInt8})
	len = length(v)
	len == 0 && return ""
	return ccall(:jl_genericmemory_to_string, Ref{String}, (Any, Int), v, len)
	end

julia> v = Memory{UInt8}(undef, 10);

julia> fill!(v, 0x01);

julia> String(v)
"\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01"

julia> v
0-element Memory{UInt8}

Maybe the current String(v::Memory{UInt8}) method could be renamed to something like take_string! to make it clear that it can mutate v.

[jakobnissen]

I think it's pretty much agreed that the truncating behaviour of String(::Vector{UInt8}) was a design mistake: #32528. It'd be unfortunate to repeat this with Memory, given that there is still time before 1.11 is released.